1. Field of the Invention
The apparatus of this invention resides in the area of combination oil/wood and coal-burning boilers, and more particularly relates to an improved shutter mechanism to seal the oil burner aperture into an oil/wood/coal-burning boiler when the oil burner is not in use.
2. History of the Prior Art
Many woodburning boilers utilize, in conjunction with their ability to burn wood, an auxiliary oil burner. The oil burner may be used during times when one is unable to load wood into the boiler or whenever one wishes to burn oil. It is important to protect the oil burner and its nozzle from the woodburning flames and heat when the oil burner is not being utilized. A closure device must be utilized which effectively seals off the oil burner from the combustion chamber of the boiler when the oil burner is not in use. Of course, the oil burner must not be sealed off while it is operating otherwise a fire could result. One device now on the market utilized to accomplish the closure of the oil burner when not in use from the combustion chamber consists of a semicircular plate which is rotatably attached at one end to a shaft adapted so that when the shaft is rotated by an electric motor, the plate is moved in and out of the way of the oil burner in an aperture between the oil burner and the boiler's combustion chamber. One problem which arises in using such a device is that it is not air-tight and many woodburning boilers, in order to achieve their high-degree of efficiency and control, must be completely sealed air-tight. Another problem is that combustion deposits tend to fall to the base of the chamber containing the rotating plate and often prevent the plate from completing its downward rotation to block the aperture in the side of the boiler through which the oil burner's nozzle shoots its flame. The failure to close this aperture completely allows heat from the burning of the wood possibly to cause damage to the oil burner nozzle and further allows unwanted air circulation in the combustion chamber thereby decreasing the control and efficiency of the wood burning boiler.